Buggy code:
public class CoreContainer { private static final String DEFAULT_DEFAULT_CORE_NAME = "collection1" ; protected static Logger log = LoggerFactory . getLogger ( CoreContainer . class ) ; protected final Map < String , SolrCore > cores = new LinkedHashMap < String , SolrCore > ( ) ; protected boolean persistent = false ; protected String adminPath = null ; protected String managementPath = null ; protected CoreAdminHandler coreAdminHandler = null ; protected File configFile = null ; protected String libDir = null ; protected ClassLoader libLoader = null ; protected SolrResourceLoader loader = null ; protected Properties containerProperties ; protected Map < String , IndexSchema > indexSchemaCache ; protected String adminHandler ; protected boolean shareSchema ; protected String solrHome ; protected String solrConfigFilenameOverride ; private String defaultCoreName = "" ; private boolean defaultAbortOnConfigError = false ; private int numCoresAbortOnConfigError = 0 ; public CoreContainer ( ) { } public Properties getContainerProperties ( ) { } public static class Initializer { protected String solrConfigFilename = null ; protected boolean abortOnConfigurationError = true ; public boolean isAbortOnConfigurationError ( ) { } public void setAbortOnConfigurationError ( boolean abortOnConfigurationError ) { } public String getSolrConfigFilename ( ) { } @ Deprecated public void setSolrConfigFilename ( String solrConfigFilename ) { } public CoreContainer initialize ( ) throws IOException , ParserConfigurationException , SAXException { } } private static Properties getCoreProps ( String instanceDir , String file , Properties defaults ) { } public CoreContainer ( String dir , File configFile ) throws IOException , ParserConfigurationException , SAXException { } public CoreContainer ( SolrResourceLoader loader ) { } public CoreContainer ( String solrHome ) { } public void load ( String dir , File configFile ) throws IOException , ParserConfigurationException , SAXException { } public void load ( String dir , InputStream cfgis ) throws IOException , ParserConfigurationException , SAXException { } private Properties readProperties ( Config cfg , Node node ) throws XPathExpressionException { } private boolean isShutDown = false ; public void shutdown ( ) { } @ Override protected void finalize ( ) throws Throwable { } public SolrCore register ( String name , SolrCore core , boolean returnPrevNotClosed ) { } public SolrCore register ( SolrCore core , boolean returnPrev ) { } public SolrCore create ( CoreDescriptor dcore ) throws IOException , ParserConfigurationException , SAXException { File idir = new File ( dcore . getInstanceDir ( ) ) ; if ( ! ( idir . isAbsolute ( ) ) ) { idir = new File ( solrHome , dcore . getInstanceDir ( ) ) ; } String instanceDir = idir . getPath ( ) ; SolrResourceLoader solrLoader = new SolrResourceLoader ( instanceDir , libLoader , CoreContainer . getCoreProps ( instanceDir , dcore . getPropertiesName ( ) , dcore . getCoreProperties ( ) ) ) ; SolrConfig config = new SolrConfig ( solrLoader , dcore . getConfigName ( ) , null ) ; if ( config . getBool ( "abortOnConfigurationError" , defaultAbortOnConfigError ) ) { ( numCoresAbortOnConfigError ) ++ ; } IndexSchema schema = null ; if ( ( indexSchemaCache ) != null ) { File schemaFile = new File ( dcore . getSchemaName ( ) ) ; if ( ! ( schemaFile . isAbsolute ( ) ) ) { schemaFile = new File ( ( ( ( ( solrLoader . getInstanceDir ( ) ) + "conf" ) + ( File . separator ) ) + ( dcore . getSchemaName ( ) ) ) ) ; } if ( schemaFile . exists ( ) ) { <START_BUG> String key = ( ( schemaFile . getAbsolutePath ( ) ) + ":" ) + ( new SimpleDateFormat ( "yyyyMMddhhmmss" , Locale . US ) . format ( new Date ( schemaFile . lastModified ( ) ) ) ) ; <END_BUG> schema = indexSchemaCache . get ( key ) ; if ( schema == null ) { CoreContainer . log . info ( ( "creating<seq2seq4repair_space>new<seq2seq4repair_space>schema<seq2seq4repair_space>object<seq2seq4repair_space>for<seq2seq4repair_space>core:<seq2seq4repair_space>" + ( dcore . name ) ) ) ; schema = new IndexSchema ( config , dcore . getSchemaName ( ) , null ) ; indexSchemaCache . put ( key , schema ) ; } else { CoreContainer . log . info ( ( "re-using<seq2seq4repair_space>schema<seq2seq4repair_space>object<seq2seq4repair_space>for<seq2seq4repair_space>core:<seq2seq4repair_space>" + ( dcore . name ) ) ) ; } } } if ( schema == null ) { schema = new IndexSchema ( config , dcore . getSchemaName ( ) , null ) ; } SolrCore core = new SolrCore ( dcore . getName ( ) , null , config , schema , dcore ) ; return core ; } public Collection < SolrCore > getCores ( ) { } public Collection < String > getCoreNames ( ) { } public Collection < String > getCoreNames ( SolrCore core ) { } public void reload ( String name ) throws IOException , ParserConfigurationException , SAXException { } private String checkDefault ( String name ) { } public void swap ( String n0 , String n1 ) { } public SolrCore remove ( String name ) { } public SolrCore getCore ( String name ) { } protected CoreAdminHandler createMultiCoreHandler ( final String adminHandlerClass ) { } public CoreAdminHandler getMultiCoreHandler ( ) { } public String getDefaultCoreName ( ) { } public boolean isPersistent ( ) { } public void setPersistent ( boolean persistent ) { } public String getAdminPath ( ) { } public void setAdminPath ( String adminPath ) { } public String getManagementPath ( ) { } public void setManagementPath ( String path ) { } public File getConfigFile ( ) { } public void persist ( ) { } public void persistFile ( File file ) { } void persist ( Writer w ) throws IOException { } private void writeAttribute ( Writer w , String name , Object value ) throws IOException { } void persist ( Writer w , CoreDescriptor dcore ) throws IOException { } private void writeProperties ( Writer w , Properties props ) throws IOException { }

Fix:
String key = ( ( schemaFile . getAbsolutePath ( ) ) + ":" ) + ( new SimpleDateFormat ( "yyyyMMddHHmmss" , Locale . US ) . format ( new Date ( schemaFile . lastModified ( ) ) ) ) ;